JP3070017B2 - Control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission for a vehicle, and more particularly to a control device for improving a shift control characteristic when traveling on an uphill or downhill.

[0002]

2. Description of the Related Art In general, a control device for an automatic transmission for a vehicle prepares a gear shift scheduling map in advance, and retrieves from an operating parameter indicating an engine load such as a throttle opening and an operating parameter indicating a vehicle speed during traveling. The gear ratio is determined. However, since the gear shift map is created based on a general traveling state, it does not always provide good shifting characteristics when traveling on an uphill or downhill. For this reason, Japanese Patent Publication No. 59-8
As disclosed in Japanese Patent No. 698, a gear shift map is separately provided according to the state of a traveling road, such as for traveling on a flat road, traveling on an uphill or downhill, and a vehicle on a flat road is determined based on operating parameters such as throttle opening and vehicle speed. A technique has been proposed in which an index indicating the running resistance of the vehicle, specifically, an expected value of the running acceleration, is obtained, the calculated value is compared with the actual vehicle acceleration calculated from the vehicle speed, and a gear shift map is selected according to the comparison result. ing.

[0003]

In this type of control, when it is determined that the vehicle is traveling on a downhill road, a low speed gear is used by switching to a map for traveling on a downhill road to improve engine braking. This makes it easier to descend on mountain roads. However, the need for engine braking is low on gentle downhill roads, and when the gear is low, the engine speed is higher than when it is high, so the noise may increase and the drive feeling may worsen. May occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device for an automatic transmission for a vehicle which solves the above-mentioned drawbacks and improves the drive feeling when traveling on a gentle downhill.

[0005]

The present invention to solve the above object In order to achieve the above was constructed as shown in item 1 請 Motomeko. See below
A description will be given in connection with an embodiment according to the present invention.
Indicates at least the vehicle operating conditions including vehicle speed and engine load.
Operating state detecting means (vehicle speed sensor 42, slot
Opening sensor 40, S10), the detected vehicle speed and machine
Expected that the vehicle will output based on the relevant load
Expected acceleration calculation means for calculating acceleration GGH (S12,
S200 to S218), the detected vehicle speed and engine load
The actual acceleration HDELV output by the vehicle based on the load is
The actual acceleration calculating means (S14, S300 to S3)
24), difference PN between the calculated expected acceleration and actual acceleration
Calculate O (PNOAVE) and PKU (PKUAVE)
And, then whether <br/>-size constant the vehicle from the difference is descending traveling slope, plural kinds of downhill previously set based on the difference
Shift characteristic corresponding to road shift characteristic (MAPS3-4)
Shift characteristic selecting means for selecting (MAPS 3 or 4)
(S16, S36, S46, S48, S700 to S7
44) determining a gear ratio according to the selected gear characteristic;
Speed ratio determining means (S50) to perform
Multiple range positions selected by the driver according to the gear ratio
Drives the transmission mechanism based on one of the positions D4, D3, and D
In the control device for an automatic transmission for a vehicle, the transmission characteristic selection means determines whether the engine load TH is equal to or greater than a predetermined value THREF.
Load determining means (S742), wherein the engine load is predetermined.
When it is determined that the value is not less than the value,
Downhill traveling speed change characteristics such that the determined speed ratio decreases
(MAPS4) is selected again (S744) .

[0006]

[Function] The fact that the engine load has exceeded the predetermined value during downhill road control indicates that the driver does not need assistance with engine braking and rather wants to accelerate, so it is decided in that case. Characteristics to reduce the gear ratio
You . As a result, the gear ratio is returned to a direction in which the gear ratio becomes relatively small, and the inconvenience described above is eliminated, so that the drive feeling can be improved.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram generally showing a control device for an automatic transmission for a vehicle according to the present invention. In the drawing, reference numeral 10 indicates an internal combustion engine. The engine output generated by the internal combustion engine 10 is sent to the transmission 14 through the shaft 12 and transmitted to the main shaft 18 via the pump impeller 16a and the turbine runner 16b of the torque converter 16.
Between the main shaft 18 and the counter shaft 20, there is provided a gear mechanism 22 consisting of four forward steps and one reverse step, and a secondary shaft 24 is arranged in parallel with the counter shaft 20. Hydraulic clutches C1 to C4 are arranged at each gear. Incidentally, the one indicated by the symbol CH is a hydraulic clutch for bypassing the one-way clutch 26. Here, the transmission output is the final gear 2
The drive wheel 34 is sent to the differential device 30 through the drive shaft 8 and drives the drive wheel 34 through the drive shaft 32. still,
The hydraulic clutch C4 is used for forward and reverse travels. When the selector 36 is located to the left in the drawing, the forward fourth speed is established, and when the selector 36 is located to the right, the reverse gear RVS is established via an idle gear (not shown).

A throttle opening sensor 40 for detecting the opening of a throttle valve (not shown) disposed in an intake passage (not shown) of the internal combustion engine 10 is provided. In the vicinity of the counter shaft 20 of the transmission 14, a vehicle speed sensor 42 for detecting the vehicle speed from the rotation speed of the shaft 20 is provided. A brake switch 44 for detecting the presence or absence of a brake operation is provided near a brake pedal (not shown).
P, R, N, D4, D are provided near a range selector (not shown) mounted on the floor of the vehicle driver's seat.
A range selector switch 46 for detecting the range position selected by the driver among the seven ranges of 3, 2, 1 is provided. The output of the throttle opening sensor 40 etc.
(Electronic control unit) 50.

The ECU 50 comprises a CPU 50a, a ROM 50
b, RAM 50c, input circuit 50d, and output circuit 50e
The sensor (switch) output is input into the microcomputer via an input circuit 50d. In the microcomputer, the CPU 50a selects a gear shift map according to the traveling path to determine a shift position (gear position) as described later in detail, and energizes the solenoid valves 54, 56 of the hydraulic control circuit through the output circuit 50e. By de-energizing, a shift valve (not shown) is switched, and a hydraulic clutch at a predetermined gear stage is released and engaged. Note that the solenoid valves 58 and 60 are for ON / OFF control of the lock-up mechanism 16c of the torque converter 16.

Next, the operation of the present control device will be described with reference to the flow chart of FIG. 2. Before that, the features of the present control device will be briefly described with reference to FIG. The expected acceleration (only for the third speed) expected of the vehicle when traveling on a flat road is set in advance according to the throttle opening and the vehicle speed. On the other hand, the actual acceleration at which the vehicle is actually generated is determined from the vehicle speed, and the actual acceleration is multiplied by a coefficient and corrected to a value corresponding to the third speed. The values are then compared and the difference PNO,
The PKU was determined and averaged, and then the corresponding gearshift map was selected (switched). Expected acceleration is E
In the CU 50, a map stored in the ROM 50b is searched for and obtained from the throttle opening and the vehicle speed.
FIG. 4 shows the characteristics of the map. Here, the expected acceleration is obtained from the throttle opening and the vehicle speed by the vehicle speed, the gear speed,
This is because, when the road is running with the same road gradient, the driving force, that is, the acceleration obtained by the engine load is different, and the running resistance, especially the air resistance, is a value proportional to the vehicle speed. In addition, five types of gear shift maps are prepared for heavy uphill, light uphill, flat road, light downhill, and heavy downhill. FIG.
FIG. 6 shows the characteristics of the map for flat roads, and FIG. 6 shows the characteristics of the map for light ascending roads (the 3rd speed region is enlarged as compared to the flat road). Although omitted for the sake of simplicity, as shown in FIG. 7, each map is provided with a hysteresis in a shift-up direction and a shift-down direction.

Returning to the flow chart of FIG.
A parameter required for the calculation is obtained with 0. For the throttle opening etc. as parameters, the sensor output value is obtained as it is,
The vehicle speed is calculated by counting the output pulses of the sensor 42 for a predetermined period of time. The change in the throttle opening is also detected in this step, so that it will be described below with reference to the flowchart of FIG. . The program shown in the flowchart of FIG. 2 is started by a timer interrupt every 20 ms.

In the flow chart of FIG.
At 00, the throttle opening THPT detected a predetermined time ago is read, and at S102, the throttle opening TH detected this time is read.
The difference (absolute value) from the US is determined and the predetermined throttle opening YD is determined.
This is compared with TTH (for example, (0.5 / 8) × WOT [degree]). When it is determined in S102 that the difference exceeds the predetermined value, that is, when it is determined that the amount of change in the throttle opening is large, the process proceeds to S104, in which the throttle sudden change timer (down counter) TM is set.
A predetermined value YTMETN is set in ETN and time measurement is started. If it is determined in S102 that the difference is smaller than the predetermined value, the program is immediately terminated.

Returning to the flow chart of FIG.
Proceeding to 12, the expected acceleration (referred to as "GGH") is obtained.

FIG. 9 is a subroutine flow chart showing the operation. Referring to FIG.
At 200, the throttle opening (the throttle opening used for map search is called "GMAPTH") and the current vehicle speed V
Then, a map search value GGBASE of the expected acceleration is obtained with reference to the map whose characteristics are shown in FIG. Note that, as described above, this value is a running acceleration that is expected to be output when the vehicle is running on a flat road using the third speed gear based on the throttle opening and the vehicle speed. Is represented by [m / s ² ]. The values shown in FIG. 4 are exemplarily described for convenience of understanding.

Next, the process proceeds to S202, where the down counter GG
After confirming that the value of CNT1 (described later) is zero, S20
In step 4, a predetermined value YGGCNT is set in the counter and the counter is started. As will be described subsequently, this counter looks at the change between the previous value of the expected acceleration and the value searched this time, and determines the pacing processing interval to gradually increase (decrease) when the change is large. That is, first, the process proceeds to S206, and the value obtained by adding / subtracting the minute value YDG1L, H to the value GGBASE searched this time is compared with the previous value GGH, and whether the change between the previous value and the current value is within the predetermined range is determined. Determine whether or not. When it is determined in S206 that it is within the predetermined range, the change amount is small,
Proceeding to S208, the map search value (current value) GGBASE is set as the current estimated acceleration GGH as it is.

If it is determined in step S206 that the change exceeds the predetermined range, the process proceeds to step S210, where the previous predicted acceleration GGH is compared with the current map search value GGBASE, and it is determined that the change is in the increasing direction. Then, the program proceeds to S212, and the program is temporarily ended with the value obtained by adding the predetermined unit amount YDG2 to the previous value GGH as the current expected acceleration GGH. Then, when the program is started next time, the counter value is decremented in S214 until it is determined in S202 that the counter value has reached zero.
In step S206, S2, the counter is newly started in step S4.
10, the process proceeds to S212, where the predetermined unit amount YDG2 is again obtained.
Is added to correct the increase. That is, as shown by the one-dot chain line in FIG. 10, when the change from the previous value is large, the predetermined amount (YDG2) is given every predetermined time (GGCNT1) until it is determined in S206 that it has reached the vicinity of the current map search value. It gradually increases.
This avoids sudden changes in expected acceleration,
Control hunting due to momentary depression of the accelerator pedal can be prevented.

This situation is the same when it is determined that the predicted acceleration searched in S210 has decreased from the previous value. In that case, the process proceeds to S216, where the throttle opening is set to the opening CTH near the fully closed state, specifically, Typically ( 0.5 / 8) x WOT
[Degree] Then, it is determined whether or not the following is true, and in S218 and S220, the decreasing unit amounts YDG3US and YDG
3 is gradually reduced to the current map search value while making 3 different. Here, the unit amount was changed because the torque fluctuation follows the change in the throttle opening more quickly when the throttle opening is below the fully closed position than in other cases. Therefore, the unit amount is also YDG3 <YDG
3US. FIG. 11 shows stepwise correction in the decreasing direction.

Returning to the flowchart of FIG. 2, the program proceeds to S14, where the actual acceleration HDELV is calculated. FIG.
2 is a subroutine flow chart showing the operation. As described above, since the expected acceleration is a value when the vehicle is running in the third gear, the actual acceleration also needs to be made to correspond to it. Therefore, in the flowchart of FIG. Is the second speed or lower, the third speed, or the fourth speed, and according to the determination result, S30
The process proceeds to steps S306 and S308 to determine a correction coefficient.
The correction coefficient is similar to the predicted acceleration map shown in FIG.
According to the throttle opening and the vehicle speed, there are three types of maps in which the value of the ratio is mapped in advance, for the first, second, third and fourth speeds. The value of the ratio is searched for and obtained from the degree GMAPTH and the vehicle speed V (the correction coefficient obtained by searching the map is referred to as "GGFBASE"). Here, the reason why the first speed and the second speed are not distinguished is that the purpose of this control is originally to improve the shift characteristics on an uphill or downhill road. Switch from the map to a map for uphill or downhill roads, but for uphill roads, shift down to increase driving power, and for downhill roads, shift down to obtain engine braking effect. Since the first gear is the lowest gear and there is no way to downshift, the same data as the second gear is used for the convenience of this control. In addition, the map of the ratio for the third speed is "10" on the data because the expected acceleration compared with the actual acceleration corrected using this ratio is for the third speed.

Then, the process proceeds to S310, in which it is confirmed that the value of the second down counter GGCNT2 is zero.
Proceeding to 312, a predetermined value YGGCNT is set in the counter and started, and it is determined whether or not the correction coefficient searched in S314 is over a predetermined range by comparing with the previous value. The same naming process as performed earlier with the expected acceleration is performed. That is, first, S31
In step 4, the current value ± YDF1L, H is compared with the previous value, and if it is within the range, the process proceeds to step S316, where the map search correction coefficient GGFBASE
Is used as it is as the correction coefficient GGF, and the process proceeds to S318 to calculate the actual acceleration HDELV by multiplying the first order difference ΔV of the detected vehicle speed value, that is, the vehicle speed change every predetermined time. If it is determined in S314 that the value exceeds the range, the process proceeds to S320, and the previous value GG
F is compared with the current value GGFBASE. If it is determined that the current value is in the increasing direction, the process proceeds to S322, where the previous value GGF is added to the previous value GGF.
The value obtained by adding YDF2 is used as the current correction coefficient. If it is determined that the value is in the decreasing direction, the process proceeds to S324, in which the decreasing unit amount YDF3
The value obtained by subtracting is used as the current correction coefficient. Each time the counter value decremented in S326 is determined to have reached zero in S310 at the next and subsequent program startups, this increase (decrease) correction is repeated until it is determined in S314 that the counter value has reached near the previous value. The reason for this configuration is to prevent a sudden change in the control value, as described in the description of the expected acceleration in the flow chart of FIG. Here, the actual acceleration is calculated from the vehicle speed difference value. However, a differential value may be obtained, and in any case, these are expressed in units [m / s ² ] equivalent to the expected acceleration.

Next, returning to the flow chart of FIG.
Proceeding to 6, the difference PNO, PKU between the expected acceleration GGH and the actual acceleration HDELV is calculated. FIG. 13 is a subroutine flowchart showing the calculation operation. Where P
KU means the difference in the downhill direction obtained by subtracting the expected acceleration GGH from the actual acceleration HDELV, and PNO means the difference obtained by subtracting the actual acceleration HDELV from the expected acceleration GGH and the difference in the uphill direction.

In the flow chart of FIG.
At step 00, the difference PKU in the downhill direction is calculated from the calculation formula just described. The reason why the order of subtraction of the difference is changed is that the actual acceleration is larger than the expected acceleration (on a flat road) on a downhill, and vice versa on an uphill. Also, calculating the difference between the time of climbing and the time of going downhill here has nothing to do with whether the vehicle is actually going uphill or downhill, and simply subtracts the expected acceleration from the actual acceleration to the difference in the downhill direction. And the reverse is simply the difference in the uphill direction. That is, since the map is selected from the average value of these values as described later, if the vehicle is actually going downhill, for example, only the difference PKU in the downhill direction should be a positive value. Since the value in the ascending direction should be zero or less, by selecting a map using only positive values, as a result, the gear ratio can be optimized in response to the gradient change without providing a tilt sensor or the like. Can be determined.

Then, the program proceeds to S402, in which it is determined whether or not the throttle opening is less than or equal to the fully-closed opening CTH. Determine if it has reached zero. As will be described later with reference to FIG. 2, this timer is set when a brake operation is performed, and starts when the brake is released. Therefore, the determination in this step is based on whether the brake operation is being performed, or more precisely, whether or not a predetermined time has elapsed since the brake was released after the brake was once depressed. That is, once the brake is depressed, even if the brake is released, the braking force does not immediately become zero due to a delay in the response of the braking system, so that it is determined that the brake operation is being performed for a predetermined time (timer value). If it is determined in S404 that the brake timer value is not zero (during the braking operation), the process proceeds to S406, where a predetermined amount YDADO5 is added and the difference PKU is calculated.
Is increased. This is to compensate for the decrease in the actual acceleration due to the braking force. Next, the routine proceeds to S408, where the actual acceleration HDELV is subtracted from the expected acceleration GGH to calculate a difference PNO in the uphill direction.

Returning to the flow chart of FIG.
The program proceeds to step 18 to determine whether or not the brake switch is on. If it is determined that the brake switch is on, the procedure proceeds to step S20, in which the brake timer TMPAVB is set to a predetermined value YTMPAVB and started (as described above, this timer value Means that once the brake-on is detected, the timer value is continuously reset each time this step is looped, and the brake pedal is released and the brake-on judgment is denied and the countdown continues without being reset. Therefore, this timer value indicates the elapsed time since the brake was turned off). Next, the process proceeds to S22, where it is determined whether or not the "D4, D3, 2" range is selected from the range selector switch signal. If the determination is affirmative, the process proceeds to S24 to determine whether the range is being switched among the three ranges. Judge,
If not, the process proceeds to S26 to start the timer TMPAHN2 (if S24 is affirmative, the process jumps S26, so that the timer value indicates the elapsed time of range switching as described in S20). Then, the program proceeds to S28, where it is confirmed from the bit of the BROK2 flag whether or not the brake signal is normal. Checking whether the brake signal is normal is performed by a separate routine (not shown). For example, when the brake switch-on signal and the brake-off signal continue for a predetermined period of time after the ignition switch is turned on, it is determined that the brake signal is normal. If not, it is determined that the brake signal is abnormal, and the result is indicated in this flag.

If it is determined in step S28 that the brake signal is normal, it is determined in step S30 whether the range is being switched again. If it is determined that the range is not being switched, the process proceeds to step S32 in which whether the timer TMPAHN has reached zero is determined. Judge. This starts when the excitation pattern of the solenoid valves 54 and 56 is switched in another subroutine (not shown), and indicates whether or not the gear is being shifted. Therefore, when the timer value has reached zero, it means that the gear is not being shifted, so the process proceeds to S34, where it is determined whether or not the current gear is the first speed, and when the result is negative, the process proceeds to S36. The average value PNOAV of the differences PNO, PKU in the uphill and downhill directions previously obtained with
E, PKUAVE, more specifically, a weighted average value is calculated. FIG. 14 is a subroutine flowchart showing the operation.

Referring to FIG. 5, the slope difference PNO calculated this time in S500 is compared with the accumulated average value (weight coefficient) PNOAVE up to that point, and the value is increased or decreased with respect to the previous value. Determine if there is. If it is determined that the value is in the decreasing direction, the process proceeds to step S502, and the smoothing coefficient KP
After NO is set to YKPNODN, the process advances to step S504, and a weighted average value is calculated from the illustrated equation. If it is determined that the throttle direction is increasing, the process proceeds to S506, where it is determined whether or not the value of the throttle sudden change timer TMETN shown in FIG. 8 is zero, that is, whether or not the throttle opening is not suddenly changed. If it is determined that the value has not been set, the process proceeds to step S508, where
OUP is set. Then, after confirming that the brake operation is not performed in S510, the process proceeds to S504 to calculate a weighted average value. If it is determined in S506 that the throttle opening is suddenly changed, S504 is jumped. Therefore, in this case, the map is determined (held) by the previously calculated average value PNOAVEn-1. As a result, it is possible to prevent the control value (map selection) from being erroneous when the throttle opening suddenly changes. The same applies when the brake is determined to be ON in S510. The apparent engine output torque decreases by the amount of the braking force generated in proportion to the driver's depressing the brake pedal, and the map search throttle opening is reduced. Since there is no corresponding engine output, S504 is jumped to use the previously calculated average value. Next, in S512, the calculated value is compared with the upper limit value YPNOCUT.
At 14, the value is rewritten to the upper limit. That is, as shown in FIG.
When the vehicle returns to a flat road after the uphill, it is necessary to quickly correct the map for the flat road, so an upper limit is provided here.

Next, the average value of the difference values in the downhill direction is calculated. That is, the current calculated value PKU is compared with the average value PKUAVE up to the previous time in S516, and when it is determined that the vehicle speed is increasing, the vehicle speed V is decreased in S518. After comparing with the predetermined vehicle speed YVOAD1 and then confirming in S520 and S522 that the throttle opening has not changed abruptly, according to the comparison result, S524 and S5 are executed.
Proceed to step 26 to select the weight coefficient KPKU,
Proceeding to 528, the current weighted average value PKUAVE is calculated. Here, changing the coefficient according to the vehicle speed is because the value of the running resistance does not increase so much when it is downhill,
This is to create an opportunity to shift down early from vehicle speed. Therefore, the value of the coefficient is set to be YKPKUUPH> YKPKUUPL, and the coefficient value is increased as the vehicle speed becomes higher, so that the current value is largely reflected on the average value. If it is determined in S520 and S522 that the throttle has suddenly changed for the same reason as described for the PNO, the jump is made to S528 and the average value up to the previous time is used.

If it is determined in S516 that the current value is in a decreasing direction with respect to the previous cumulative average value, it is determined that the vehicle is descending downhill. After confirming that there is, proceed to S532,
After confirming that the brake operation is not being performed, the process proceeds to S534, and similarly, one of the smoothing coefficients is selected according to the vehicle speed and the average value is obtained (S536, S538, S52).
8). Here, the coefficient is set to be large on the high vehicle speed side for the same reason as the increasing direction. Next, it is determined whether or not the calculated value exceeds the upper limit value in S540 and subsequent steps.
Limit to 2 at the upper limit. This is to correct the detection delay when returning to a flat road as in the case of climbing a hill, as shown in FIG. When it is determined that the brake operation is being performed in S532, it is difficult to obtain an accurate value in the same manner as described in S510. Therefore, the process immediately proceeds to S540 and S542, and the average value uses the previous value.

Returning to FIG. 2, when the conditions from S18 to S34 are satisfied, the process proceeds to S36 to calculate the difference average value as described above. Here, the condition is satisfied in FIG. The case in which it is not performed will be described. First, S22
If the determination is negative, that is, if it is determined that the vehicle is in the P, R, N, 1 range, there is no need to perform the uphill and downhill control, so the process proceeds to S38, and the timer started in S26 for determining the range switching elapsed time is determined. It becomes unnecessary and is reset, and the process proceeds to S42 to set the average difference value to “0”. As a result, a map for a flat road is selected as described later. This is the same when the brake signal is determined to be abnormal in S28. If it is determined in S30 that the range switching is being performed, and if it is determined in S40 that the timer value has reached zero, it takes a long time to switch the range, and it is not considered to be in a normal state. Since it is understood that the error has occurred, the process similarly jumps to S42. In order to maintain continuity of this control until it is determined in S40 that the timer value has reached zero, the process proceeds to S44 and proceeds to S44 in the flow chart of FIG. The average value uses the previous value. The same applies to the case where it is determined in S32 that the gear is being shifted. If the gear is being shifted, the gear position cannot be determined and the acceleration is not stable, so that the process also proceeds to S44 to use the previous average value. Also, when it is determined in S34 that the vehicle is currently in the first speed, the same is applied in the sense of simplifying the calculation, since there is no possibility of downshift below that.

In the flow chart of FIG.
Proceeding to 46, the work of discriminating the uphill / downhill MAPS1,2 is performed. Here, "MAPS1,2 discriminating work" will be described. Five types of shift maps prepared according to the gradients include 0, 1, 2, and 3.
This is an operation in which five numbers 3 and 4 are assigned and the maximum value and the minimum value that can be obtained from the difference average value just obtained are the values of MAPS1,2. Referring to the subroutine flow chart of FIG. 16 showing the operation, FIG.
In 600 to S606, the average value PNOAVE in the ascending direction is compared with the map reference value PNOmn, respectively, and then in S608 to S6.
In step 14, the average value PKUAVE in the downhill direction is compared with the map reference value PKUmn. As a result, S616 to S
632 is the minimum value that can be selected (“MAPS
1 ”) and the maximum possible value (“ MAPS2 ”) are determined.
FIG. 17 shows a map reference value set corresponding to the difference average value.

That is, in this control, as described above,
Five types of maps are prepared, and numbered as follows to specify them. 0: Map for heavy climbing 1: Map for light climbing 2: Map for flat road 3: Map for light descending 4: Map for heavy descending Here, a hysteresis area is provided between each map as shown in FIG. Therefore, when the difference average value is located there, any of the adjacent maps can be taken. Therefore, in this work, the maximum value and the minimum value (with respect to the map number) that can be taken are determined for the time being. FIG. 18 shows a selection result of the flow chart of FIG. It should be noted that, from FIG. 17, S in the flow chart of FIG.
It will be appreciated that a flat road map is selected by zeroing the difference average at 42.

Therefore, returning to the flow chart of FIG. 2, one of the two types of maps determined in the next S48 is finally determined.

Referring to the subroutine flowchart of FIG. 19, first, in S700, the currently selected map (referred to as "MAPS") and MAPS2 (maximum map).
Compare. That is, logically, the map to be selected may be determined so that the maximum map ≧ the selection map ≧ the minimum map. First, it is determined whether or not the current map exceeds the maximum map. Change the selected map so that it is less than or equal to the maximum map value.

Therefore, when it is determined in S700 that the current map exceeds the maximum map, assuming that the current map number is the minimum value 0, the map numbers "1, 2, 3, 3"
4 "(map number 0 is impossible because it exceeds" 0 "), so it is determined in S702 whether or not the current map is number 2 (flat road map). When it is done, the map number will be called "3, 4" and it will be called a downhill road map,
In S704, the map is determined by subtracting “1” from the current map number. For example, when a heavy downhill road map is currently used, the map is switched to a light downhill map. If the current map is determined to be equal to or smaller than the map for flat roads in S702, it will be one of "2, 1", and switching from flat road use to light climbing or light climbing to heavy climbing will be performed. As shown in FIGS. 5 and 6, the map used in this control has a third speed region for a light climbing road compared to a flat road.
In addition, it is set so as to be enlarged for heavy climbing roads as compared with light climbing roads. This is the same on the downhill side, and the third speed region is expanded as the vehicle goes down from a flat road to a light downhill and a heavy downhill.
This is set to increase the driving force when climbing uphill and to use the engine brake when going downhill. As a result, when the vehicle is currently in 4th gear, the map is switched to 3rd gear immediately. There is a risk of being downed, which is an undesirable downshift that the driver does not expect. In order to avoid this, it is determined in S706 whether the current gear position is the third speed or not. Only when it is determined that the speed is the third speed or less, the map is changed from a flat road to a light uphill or from a light uphill to a heavy uphill. I switched to. Therefore, when the vehicle is in the fourth speed, the map switching is stopped.

If it is determined in S700 that the current map is equal to or smaller than the maximum map, the condition on the upper limit is satisfied, and the determination is subsequently made on the lower limit. That is, in S708, the current map (number) is MAPS1 (minimum map (number)).
It is determined whether or not the map is greater than or equal to the minimum map.

If it is determined in step S708 that the current map (number) is less than the minimum map, it is necessary to correct the value to a value equal to or greater than the minimum map. Then, in S710, the current map is compared with the flat road map. If the current map is determined to be smaller than for a flat road, the map to take is "
In step S712, the current map is incremented by adding 1 to the current map. Therefore, if the light climbing map is currently used, the current weight is added to the flat road map. If the uphill map is used, the map is switched to the light uphill map.If it is determined in S710 that the current map is equal to or greater than the flat road map, the current map number is "2" or "3" ( Since it is determined that the minimum map is smaller than the minimum map in S708, "4" is not possible even if the minimum map is assumed to be the maximum value 4.) "2" or "3"
In the case of the addition from, there is a problem of expansion of the third speed range, so the process proceeds to S714 to determine whether or not the vehicle is currently at or below the third speed. In S712, the map is switched immediately, and when it is determined that the fourth speed is selected, the current map (number) is compared with the flat road map (number) in S716. If it is determined in S716 that the current map (number) is a flat road map, the process proceeds to S718, where the vehicle speed is compared with a predetermined value YKUV1, and the current map (number) is not a flat road map. If it is determined that the map is for a light downhill, the process proceeds to S720 and the vehicle speed is changed to another predetermined value YKUV.
If the vehicle speed is determined to be equal to or higher than the predetermined value in these steps, the process jumps to S712 to switch the map. This will be described with reference to FIG. 20. As described above, the third speed region is expanded in the uphill / downhill map as compared with the flat road map, but specifically, from the flat road to light downhill. The boundary vehicle speed line from the third speed to the fourth speed for the slope is set as shown by the vehicle speed YKUV1 in FIG. Therefore, when the vehicle speed is higher than the boundary vehicle speed, there is no possibility of downshifting.
Proceeding to 12, the map is switched. On the other hand, if it is determined that the vehicle speed is lower than the boundary speed, there is a danger of downshifting.
It is determined in the following steps whether a downshift occurs. FIG. 20 shows switching from the flat road map (No. 2) to the light downhill map (No. 3). The map from the light downhill map (No. 3) to the heavy downhill map (No. 4) is shown.
The same applies when switching to.

When it is determined in S718 and S720 that the current vehicle speed is lower than the boundary vehicle speed, the process proceeds to S722, in which it is determined whether or not the throttle opening is equal to or less than the vicinity of the fully closed position. If it is denied, it means that the accelerator pedal is being depressed, and it means that the accelerator pedal is being depressed at the 4th speed. In any case, the driver does not intend to decelerate using the engine brake by downshifting, so that the map is not switched by jumping S712.

When it is determined in S722 that the throttle opening is less than or equal to the fully-closed state, the accelerator pedal is not depressed, indicating the driver's intention to decelerate. If the map is for a flat road, the process jumps to S712 to switch the map. If the map is denied, the current map is referred to as a light downhill road map, so the process proceeds to S726. It is determined whether or not the brake operation is being performed to determine whether or not the driver truly has a deceleration intention. When the brake operation is not performed, it is considered that the driver does not have the intention to decelerate, and thus the step S712 jumps and the map is not switched. S7 when it is determined that the brake is being operated
28 to S730, the current vehicle speed V is set to the predetermined value YVOAD1,2
S732, S734, S736
, The deceleration data (described later) is selected, and the deceleration data selected in S738 is compared with the actual deceleration DTV and the amount of decrease in the vehicle speed per unit time during the brake operation, and the actual deceleration DTV is larger. In this case, it is determined that the vehicle is suddenly decelerating, and the process proceeds to S712 to switch the map. This is to prevent abrupt engine braking (due to downshifting), since the deceleration during downshifting is greater at higher vehicle speeds, even if the driver intends to decelerate while the brake is being applied. The map is not switched unless the deceleration by the brake increases as the vehicle speed increases. Therefore, only when it is determined from the comparison result that rapid deceleration is intended, map switching is performed to downshift. FIG. 21 shows the relationship between the deceleration data.

Subsequently, the program proceeds to S740, in which it is determined whether or not the determined map (number) is "4" (for heavy downhill). If affirmative, the program proceeds to S742, in which the throttle opening TH is set to a predetermined value.
THREF, specifically, it is determined whether or not it is equal to or more than (2/8) × WOT [degree], and if affirmative, the process proceeds to S744 to forcibly rewrite the map (number) to 3 (for light slope). I made it.
This point will be described with reference to FIG. 22. The heavy downhill map is selected because the third speed region is set to be further expanded in the heavy downhill map as compared to the light downhill map. Thus, the third gear is frequently used. On the other hand, as described earlier, the need for engine braking is low on gentle downhill roads, and the use of low-speed gears increases the engine speed and increases noise. Therefore, when the throttle opening is depressed by a predetermined value THREF or more, it is determined that the driver has not requested the assistance of the engine brake, and rather, the map is switched to the one for light descent assuming that acceleration is desired. I did it. As a result, as shown in the figure, there is a high possibility that the vehicle is shifted up to the fourth speed, and the drive feeling when traveling on a gentle downhill road can be improved. Note that the characteristics shown in FIG. 22 are simplified for convenience of understanding.

Returning to the flowchart of FIG. 2 again, the program proceeds to S50, where a shift position (gear position) is determined from the vehicle speed and the throttle opening based on the determined (switched or held) map. . Since this operation is well known and does not have the gist of the present invention, further explanation is omitted.

In this embodiment, as described above, the expected acceleration indicating the running resistance of the vehicle is obtained from the throttle opening, and the road surface gradient is estimated by comparing with the actual acceleration to switch to the descending (uphill) slope map. When driving on a slope, the drivability on a downhill is improved by engine braking using the map for heavy (light) downhill roads, and when the map for heavy downhill roads is selected, the throttle opening is depressed and the engine brake When it is determined that the assistance is not necessary, the map is switched to the light downhill road map and the upshift can be performed, so that a good drive feeling can be given even when descending a gentle downhill road.

[0042]

Although five types of maps are used, the number of maps may be reduced by making the same for light uphill and for light downhill.
Further, the characteristic may be corrected according to the average value of the difference between the expected acceleration and the actual acceleration using only one map. In the embodiment, the map is switched, but the map is not changed, and no correction (correction) is performed by using only one map. The control may not be performed when the accelerator pedal is depressed so as to return to the map control at the same time as the end of the downhill determination and the road becomes flat.

Although acceleration is used as a parameter indicating running resistance, the invention is not limited to this, and any parameter may be used as long as it indicates an index corresponding to running resistance, particularly gradient resistance. Although the actual acceleration is obtained from the vehicle speed, it may be directly detected by using an acceleration sensor.

Although the throttle opening is used as a parameter indicating the engine load, the accelerator pedal depression amount may be used.

[0046]

In the claims 1 according to the present invention, are used gear of the low speed side in the descending slope traveling, the driver engine braking with, through the engine load change downhill when the drivability is improved by the engine brake Judgment is made as to whether assistance is requested, and when it is judged that it is not necessary, the downhill control is stopped, so it is possible to use relatively high gears, for example, when going down a gentle slope. becomes also noise caused by the engine speed can be suppressed, it is possible to provide good drive Fi over ring.

[0047]

[0048]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram generally showing a control device for an automatic transmission for a vehicle according to the present invention.

FIG. 2 is a main flow chart showing an operation of an ECU (electronic control unit) in FIG.

FIG. 3 is an explanatory block diagram functionally showing features of the control device;

FIG. 4 is an explanatory diagram showing characteristics of expected acceleration used in the flow chart of FIG. 2;

FIG. 5 is an explanatory diagram showing characteristics of a flat road map used in the flow chart of FIG. 2;

FIG. 6 is an explanatory diagram showing characteristics of a light climbing map used in the flow chart of FIG. 2;

FIG. 7 is an explanatory diagram showing a hysteresis characteristic of a flat road map and the like used in the flow chart of FIG. 2;

FIG. 8 is a subroutine flowchart showing a throttle opening change amount detecting operation in the flowchart of FIG. 2;

FIG. 9 is a subroutine flowchart showing an expected acceleration calculation operation in the flowchart of FIG. 2;

FIG. 10 is an explanatory diagram showing a naming process when a change in an expected acceleration in the flowchart of FIG. 9 is large in an increasing direction;

FIG. 11 is an explanatory diagram showing the naming process when the change in the predicted acceleration in the flowchart of FIG. 9 is large in the decreasing direction.

FIG. 12 is a subroutine flowchart showing an actual acceleration calculation operation in the flowchart of FIG. 2;

FIG. 13 is a subroutine flow chart showing an operation of calculating a difference between an expected acceleration and an actual acceleration in the flow chart of FIG. 2;
It is a chart.

FIG. 14 is a subroutine flowchart showing an operation of calculating a difference average value in the flowchart of FIG. 2;

FIG. 15 is an explanatory diagram showing characteristics of an upper limit used in the flowchart of FIG. 14;

FIG. 16 is a subroutine flowchart showing a map determination operation in the flowchart of FIG. 2;

FIG. 17 is an explanatory diagram showing a determination operation of the flow chart of FIG. 16;

FIG. 18 is an explanatory diagram showing a determination result of the flowchart of FIG. 16;

FIG. 19 is a subroutine flowchart showing a map determination operation in the flowchart of FIG. 2;

20 is an explanatory diagram showing characteristics of a boundary vehicle speed from a map for a flat road to a map for a light ascending road used in the flow chart of FIG. 19;

FIG. 21 is an explanatory diagram showing a relationship between deceleration data used in the flow chart of FIG. 19;

FIG. 22 is an explanatory diagram illustrating forcible switching of the map in the flowchart of FIG. 19;

[Explanation of symbols]

 Reference Signs List 10 internal combustion engine 14 transmission 40 throttle opening sensor 42 vehicle speed sensor 44 brake switch 46 range selector switch

Continuation of front page (72) Inventor Takafumi Maruyama 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-63-111351 (JP, A) JP-A-64-30959 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-63/12

Claims (1)

(57) [Claims] 1. The method of claim 1, wherein a . Vehicle including at least vehicle speed and engine load
Operating condition detecting means to detect the operating state, b. The vehicle based on the detected vehicle speed and engine load
Acceleration to calculate the expected acceleration that is expected to output
Degree calculating means, c . The vehicle based on the detected vehicle speed and engine load
But the real acceleration calculating means for de San actual acceleration to output, d. Calculate the difference between the calculated expected acceleration and actual acceleration
And, then whether <br/>-size constant the vehicle from the difference is descending traveling slope, plural kinds of downhill previously set based on the difference
Shift characteristics that select the appropriate shift characteristics from road shift characteristics
Selecting means, e . Determining a gear ratio according to the selected gear characteristic
Speed ratio determining means, and f . Selected by the driver according to the determined gear ratio.
The transmission mechanism based on one of a plurality of range positions
Transmission means for driving, in the control system for an automatic transmission for a vehicle equipped with the variable
Speed characteristic selecting means; g . Engine load where the engine load is determined whether more than a predetermined value
Determining means, when the engine load is determined to be a predetermined value or more,
The speed ratio determined by the speed ratio determining means decreases.
A control device for an automatic transmission for a vehicle, characterized in that such a downhill traveling speed change characteristic is selected again .